I can't speak for everyone, but for myself, I may stop someone if they drew attention to themselves by doing something stupid, like jumping approaches, but in a mass evacuation it is an emergency. Also if you are off road I'll never catch you.
As a sidelight I used to race and ride as a kid. There wasn't a cop that could catch me either. <img src="/images/graemlins/blush.gif" alt="" />
As long as you had proof that you owned the machine you should be OK. There are however in any line of work there are "Rookies" who are by the book regardless of circumstances, so you are taking your chances. The main problem I see is getting home after the storm, tec. has passed. Then the laws will be enforced and you could have trouble.
Dual sport bikes on the other hand are a great alternative and with the addition of an oversized (enduro) tank they are good for a long way. Also most street bikes are better off road than their owners give them credit for, just stay out of the deep sand and mud. Even with a stock gas tank they get about 40+ mpg and with a two gallon tank thats 80 miles. If you strap on a 2 1/2 gallon spare you have almost 200 miles.
Oh the other thing that may get you noticed is strapping long guns onto the bike. Some cops get funny about that especially in urban areas. I still have an old Honda CT90 (looks like a girl's bicycle) that I use for bird hunting in the fall. In fact I was just waiting for my boys to get off the school bus so we can go. Take care, and stay safe.
It is still better to be tried by twelve than carried by six.
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It's a Jungle out there.